C2C stands for Cache To Cache.
The perf c2c tool provides means for Shared Data C2C/HITM analysis.
It allows you to track down the cacheline contentions.
On x86, the tool is based on load latency and precise store facility
events provided by Intel CPUs. On PowerPC, the tool uses random
instruction sampling with thresholding feature.
These events provide: - memory address of the access - type of the
access (load and store details) - latency (in cycles) of the load
access
The c2c tool provide means to record this data and report back access
details for cachelines with highest contention - highest number of
HITM accesses.
The basic workflow with this tool follows the standard record/report
phase. User uses the record command to record events data and report
command to display it.

-e, --event=
Select the PMU event. Use perf mem record -e list to list
available events.
-v, --verbose
Be more verbose (show counter open errors, etc).
-l, --ldlat
Configure mem-loads latency. (x86 only)
-k, --all-kernel
Configure all used events to run in kernel space.
-u, --all-user
Configure all used events to run in user space.

The Node field displays nodes that accesses given cacheline offset.
Its output comes in 3 flavors: - node IDs separated by , - node IDs
with stats for each ID, in following format: Node{cpus %hitms
%stores} - node IDs with list of affected CPUs in following format:
Node{cpu list}
User can switch between above flavors with -N option or use n key to
interactively switch in TUI mode.

User can specify how to sort offsets for cacheline.
Following fields are available and governs the final output fields
set for caheline offsets output:
tid - coalesced by process TIDs
pid - coalesced by process PIDs
iaddr - coalesced by code address, following fields are displayed:
Code address, Code symbol, Shared Object, Source line
dso - coalesced by shared object
By default the coalescing is setup with pid,iaddr.

This page is part of the perf (Performance analysis tools for Linux
(in Linux source tree)) project. Information about the project can
be found at ⟨https://perf.wiki.kernel.org/index.php/Main_Page⟩. If
you have a bug report for this manual page, send it to
linux-kernel@vger.kernel.org. This page was obtained from the
project's upstream Git repository
⟨http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git⟩ on
2019-05-09. (At that time, the date of the most recent commit that
was found in the repository was 2019-05-08.) If you discover any
rendering problems in this HTML version of the page, or you believe
there is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
perf 03/06/2019 PERF-C2C(1)